no you would need to reset your ticker once AF arrives. Your first full flow day is CD1. So if you get some spotting one day, then proper period the next, the spotting doesnt count.
BUT, as AF is still nowhere to be seen for you, I would be peeing on OPKS every day, just in case ovulation was really late for some reason this month or hasnt even happened yet. Will be easier to keep track of once AF is here.
Tesco cheapie OPKS are fine, but i backed them up around the time i thought i should be ovulating with digi ones but both gave me positives on the same day. xx